John Lunn, Juan Castellanos-Rosas, and Gilles Walch
DEFINITION
Glenoid bone loss after anterior dislocation is the loss of bone due to fracture, abrasion, or compression at the anteroinferior glenoid.
This bone loss is frequently seen after anterior dislocation and varies greatly in its extent and significance.4,6
The use of a coracoid bone block to prevent anterior dislocation was first proposed by Latarjet7 in 1954.
In 1958 Helfet5 described the Bristow technique, in which the tip of the coracoid is sutured to the capsuloperiosteal elements of the anterior glenoid. This was later modified to screw fixation.
Patte9 described the effectiveness of the Latarjet procedure as being due to the “triple blocking effect”:
The effect of the conjoint tendon when the arm is in the abducted and externally rotated position, where it acts as a sling on the inferior subscapularis and the inferior capsule (FIG 1).
The effect of the anterior bone block
The effect of repairing the capsule to the stump of the conjoint tendon
The original technique described by Latarjet involved cutting the subscapularis tendon, but this has been modified to a subscapularis split, thus preserving the integrity of its fibers.
ANATOMY
The glenoid has a pear shape, with an average height of 35 mm and an average width of 25 mm.
The fibrous glenoid labrum provides attachment for the glenohumeral ligaments to the bony glenoid and increases the depth of the glenoid by 50%.
The inferior glenohumeral ligament (IGHL) attaches to the glenoid between the 2 o'clock and 4 o'clock positions in a right shoulder.
FIG 1 • A. In normal circumstances the subscapularis provides no inferior support. B. Completed Latarjet procedure with the arm in neutral. C. The inferior displacement of the subscapularis creates a sling beneath the inferior capsule, especially in the abducted, externally rotated at-risk position.
The coracoid is directed anteriorly and then hooks laterally and inferiorly from its origin on the anterior scapular neck.
The distal and lateral coracoid is the portion osteotomized for the Latarjet procedure. It is the origin for the short head of biceps and the coracobrachialis tendons (conjoint tendon) at its tip. Medially the pectoralis minor is attached, and laterally there is the insertion of the coracoacromial and the coracohumeral ligaments.
Proximal to the “knee” of the coracoid and untouched by the osteotomy are the conoid and trapezoid ligaments.
The musculocutaneous nerve enters the conjoint tendon from the medial aspect on its deep surface at an average of 5 cm from the tip of the coracoid (range 1.5 to 9 cm).
The axillary nerve runs on the anterior surface of the subscapularis muscle lateral to the axillary artery before it enters the quadrilateral space at the inferior portion of the subscapularis.
The anterior inferior glenohumeral ligament lies deep to the middle and lower portions of the subscapularis muscle.
PATHOGENESIS
Anterior glenoid bone loss occurs because of either impaction of the humeral head on the anterior glenoid at the moment of dislocation or recurrent subluxation or dislocation.
Acute impaction may result in anteroinferior glenoid fractures, the so-called bony Bankart lesions.
Recurrent subluxation or dislocation may also result in erosion or impaction of the glenoid rim.
Recurrent dislocation occurs owing to multiple factors, one of which is the presence of a bony lesion.
Following Bankart repair, loss of external rotation is 25 degrees per centimeter of anterior glenoid defect. This is due to anterior capsular tightness.6
An osseous defect with a width that is at least 21% of the glenoid length may cause instability.6
The normally pear-shaped glenoid assumes the shape of an inverted pear.
Redislocation in contact athletes after arthroscopic anterior stabilization occurs more frequently in those with anterior bone loss.3
NATURAL HISTORY
Bone loss of varying degrees is seen in 90% to 95% of individuals with anterior shoulder instability.4,10
This bone loss occurs more frequently with recurrent dislocation than subluxation.4
A bony fragment was seen in 50% of 100 cases in a series using CT reconstruction, of which only one fragment was greater than 20% of the glenoid surface area.10
PATIENT HISTORY AND PHYSICAL FINDINGS
The history should include the mechanism of dislocation (although this is often not clear), the site of the pain, maneuvers required for reduction, recurrence, and associated injuries.
Recurrent anterior subluxation may be difficult to diagnose. A history of pain in the abducted externally rotated arm, pain resulting in a temporarily useless arm (dead arm syndrome), and more subtle variations can occur. Diagnosis is aided by a good clinical examination and imaging showing lesions of passage.
The clinician should always assess for axillary nerve injury by checking sensation in the regimental badge area and motor power in the deltoid.
Clinical examination should include.
Sulcus sign: presence suggests multidirectional hyperlaxity
External rotation with elbow at side: more than 90 degrees suggests multidirectional hyperlaxity
Anterior and posterior drawer tests: positive results suggests multidirectional hyperlaxity
Anterior apprehension test: apprehension anterior instability
Posterior apprehension test: positive apprehension suggests posterior instability
Gagey sign: Asymmetric difference in abduction of more than 30 degrees implies severe IGHL distention.
IMAGING AND DIAGNOSTIC STUDIES
Plain radiographs should include anteroposterior (AP) views in neutral, internal and external rotation, and a profile view of the glenoid (ie, as per Bernageau2) of the normal and abnormal sides (FIG 2A,B).
Radiographic accuracy and quality are improved when images are taken with fluoroscopic assistance.
CT scanning may supplement radiographs (FIG 2C).
FIG 2 • A. This patient had recurrent dislocation of his shoulder; note the normal contour of the anterior glenoid on the unaffected side. B. The bone loss at the anterior border of the glenoid on the side with recurrent dislocation is clearly seen (Cliff sign). C. The CT scan also illustrates the bone loss.
DIFFERENTIAL DIAGNOSIS
Posterior dislocation
Posterosuperior cuff pathology in throwers
Voluntary subluxation or dislocation
Recurrent subluxation or dislocation
SURGICAL MANAGEMENT
Preoperative Planning
Preoperative radiographs are analyzed to establish the presence and size of any bony glenoid defect.
We use the Latarjet procedure for all individuals with anterior instability requiring surgery. The size of the glenoid defect does not change our operative technique.
MRI or CT scans are not part of the standard preoperative planning but may assist in the diagnosis in cases of subtle instability.
The presence of large Hill-Sachs lesions, SLAP lesions (superior labrum, from anterior to posterior), or other intra-articular pathology has no influence on outcome after the Latarjet procedure and hence does not influence the operative technique.
Positioning
Under general anesthesia in association with an interscalene block for postoperative pain control, the patient is placed in the beach-chair position.
A folded sheet is placed under the scapula to reduce scapula protraction and enable better access to the coracoid and glenoid (FIG 3).
The arm is draped free to allow intraoperative abduction and external rotation.
FIG 3 • Placement of the folded sheet on the medial border of the scapula reduces scapula protraction, making it easier to place your drill holes in the glenoid parallel to the articular surface.
Approach
A deltopectoral approach is used.
The skin incision is from the tip of the coracoid extending 4 to 5 cm toward the axillary crease.
The cephalic vein is taken laterally and its large medial branch is ligated.
A self-retaining retractor is used to maintain exposure between the deltoid and pectoralis major.
The arm is placed in abduction and external rotation and a Hohmann retractor is placed over the top of the coracoid process.
TECHNIQUES
CORACOID OSTEOTOMY AND PREPARATION
Maintain the arm in abduction and external rotation to tension the coracoacromial ligament, which is incised 1 cm from its coracoid attachment.
Partially incise at the same time the coracohumeral ligament lying deep to the coracoacromial ligament and free the upper lateral aspect of the superior conjoint tendon (TECH FIG 1A).
Now adduct and internally rotate the arm to allow exposure of the medial side of the coracoid process. The pectoralis minor is released from this attachment with electrocautery, taking care not to go past the tip of the coracoid and damage its blood supply.
A periosteal elevator is then used to remove any soft tissue from the undersurface of the coracoid. This elevator also aids visualization of the “knee” of the coracoid, which is the site of the osteotomy.
Using a 90-degree oscillating saw, the osteotomy is made from medial to lateral.
The arm is then placed in abduction and external rotation for the second time. The coracoid is grasped with a toothed forceps and any remnants of the coracohumeral ligament are released.
TECH FIG 1 • A. After release of the pectoralis minor and division of the coracoacromial ligament, the osteotomy is made distal to the coracoclavicular ligaments. B. The coracoid is delivered onto a swab at the inferior part of the wound and held with a pointed grasping forceps. C. All cortical bone must be removed from this surface. D. A 3.2-mm drill is used to drill the holes.
The arm is then returned to a neutral position and the coracoid is delivered onto a swab at the inferior aspect of the wound (TECH FIG 1B).
Preparation of the bed of the coracoid is important to avoid a pseudarthrosis. Soft tissue is removed with a scalpel and then the oscillating saw is used to remove the cortical bone, exposing a cancellous bed for graft healing (TECH FIG 1C).
An osteotome is placed beneath the coracoid to protect the skin and two drill holes are made using a 3.2-mm drill (TECH FIG 1D). The holes are in the central axis of the coracoid and about 1 cm apart.
The swab protecting the skin is removed, the arm is externally rotated, keeping the elbow by the side, and the lateral border of the conjoint tendon is released for about 5 cm using a Mayo scissors.
The coracoid is then pushed beneath the pectoralis major, exposing the underlying subscapularis muscle.
GLENOID EXPOSURE
Identify the superior and inferior margins of the subscapularis; the location for the subscapularis split is at the junction of its superior two thirds and inferior one third (TECH FIG 2A).
A Mayo scissors is used to create the split. It is pushed between the fibers as far as the capsule, then opened perpendicular to the plane of the muscle fibers. Keeping the scissors open, push a small swab into the subscapular fossa in a superomedial direction and then place a Hohmann retractor on the swab in the subscapularis fossa (TECH FIG 2B).
Using a curved retractor such as a Bennett retractor on the inferior part of the subscapularis, extend the lateral part of the split with a scalpel to the lesser tuberosity. The joint line is then more easily visualized and incised for about 1.5 to 2 cm, allowing a retractor to be placed in the joint (Trillat or Fukuda retractor; TECH FIG 2C).
TECH FIG 2 • A. After drilling the holes in the coracoid, the subscapularis is split at the junction between its superior two thirds and its inferior one third. B. A small sponge is placed superomedially between the capsule and the subscapularis muscle. C. It is important to ensure the subscapularis split has been carried sufficiently laterally to allow easy visualization of the joint line.
Superior exposure is created when a Steinmann pin is hammered into the superior scapular neck as high as possible.
The medial Hohmann retractor is now exchanged for a link retractor and placed as medial as possible on the scapula neck.
A small Hohmann retractor is placed inferiorly between the capsule on the inferior neck and the inferior part of the subscapularis.
The anteroinferior part of the glenoid should now be easily visualized.
PREPARATION OF THE GLENOID AND CORACOID FIXATION
The anteroinferior labrum and periosteum are incised with the electrocautery, exposing the glenoid 2 cm medially and from about 5 o'clock to 2 o'clock in a right shoulder (a vertical distance of 2 to 3 cm).
An osteotome is then used to elevate this labral–periosteal flap from lateral to medial (TECH FIG 3A). The frequent presence of a Bankart lesion makes this quite simple.
The osteotome is then used to decorticate this anteroinferior surface of the glenoid. We aim to create a flat surface on which to place our graft.
The use of bone graft (excepting the coracoid process) is not required.
Using the 3.2-mm drill, drill the inferior hole in the glenoid (TECH FIG 3B). This is at the 5 o'clock position, parallel to the plane of the glenoid and sufficiently medial that the coracoid will not overhang the glenoid (generally 7 mm, but depends on coracoid morphology). Both anterior and posterior cortices are drilled.
The coracoid is now retrieved from its position under the pectoralis major and grasped at the cut end in a medial–lateral fashion.
A 4.5-mm partially threaded malleolar screw is fully inserted into the inferior hole (tendinous end). The length of this screw is typically 35 mm but can be verified by adding together the depth of the coracoid and the depth of the glenoid hole (TECH FIG 3C).
The screw is then placed into the already drilled inferior hole and tightened into position, ensuring that the coracoid comes to lie parallel to the anterior border of the glenoid with no overhang. A slightly medial position (2 to 3 mm) is acceptable. Rotation of the coracoid is adjusted using a heavy forceps.
When the position of the coracoid is parallel to the glenoid, the second drill hole is made through the superior hole already drilled in the coracoid (TECH FIG 3D). It is important to avoid rotation of the coracoid at this stage.
TECH FIG 3 • A. With an osteotome, cancellous bone is exposed on the glenoid neck. B. First glenoid drill hole. C. The coracoid increases the width of the anteroinferior bony glenoid. D. View after fixation of the coracoid to the glenoid neck.
The hole is measured and the correct-sized malleolar screw is inserted into position.
Repair of the capsule is then carried out by suturing the capsule to the stump of the coracoacromial ligament using a number 1 Dexon suture with the arm in external rotation, after removing the intra-articular retractor.
The retractors are removed, as is the sponge that was on the medial scapula neck.
There is no need to close the split in the subscapularis muscle.
POSTOPERATIVE CARE
A simple sling is used for 2 weeks.
Rehabilitation begins on the first postoperative day with gentle active range-of-motion exercises.
Full activities of daily living are allowed at 6 weeks and a return to all sports is permitted at 3 months.
OUTCOMES
In a study of 160 Latarjet procedures, we had a recurrence rate of 1%. Of those who played sports, 83% returned to their preinjury level or better. Overall, 98% rated their result as excellent or good and 76% had excellent or good results using the modified Rowe score.11
The occurrence of postoperative shoulder arthritis is related to preventable factors (ie, lateral overhang of the coracoid) and pre-existing factors (eg, increased age at the time of first dislocation, increased age at the time of surgery and the presence of arthritis before to surgery).
COMPLICATIONS
Intraoperative fracture of the coracoid
Infection
Hematoma formation
Pseudarthrosis (not associated with poor outcome)
Pain related to screws (2% incidence of screw removal)
Recurrence
Arthritis (if graft overhangs the anterior glenoid)
REFERENCES
1. Allain J, Goutallier D, Glorion C. Long-term results of the Latarjet procedure for the treatment of anterior instability of the shoulder. J Bone Joint Surg Am 1998;80A:841–852.
2. Bernageau J, Patte D, Bebeyre J, et al. Interet du profile glenoidien dans les luxations recidivantes de l'epaule. Rev Chir Orthop 1976; 62:142–147.
3. Burkhart SS, De Beer JF. Traumatic glenohumeral bone defects and their relationship to failure of arthroscopic Bankart repairs: significance of the inverted-pear glenoid and the humeral engaging HillSachs lesion. Arthroscopy 2000;16:677–694.
4. Edwards TB, Boulahia A, Walch G. Radiographic analysis of bone defects in chronic anterior shoulder instability. Arthroscopy 2003;19:732–739.
5. Helfet AJ. Coracoid transplantation for recurring dislocation of the shoulder. J Bone Joint Surg Br 1958;40B:198–202.
6. Itoi E, Lee SB, Berglund LJ, et al. The effect of a glenoid defect on anteroinferior stability of the shoulder after Bankart repair: a cadaveric study. J Bone Joint Surg Am 2000;82A:35–46.
7. Latarjet M. A propos du traitement des luxations recidivantes de l'epaule. Lyon Chir 1954;49:994–1003.
8. May VR Jr. A modified Bristow operation for anterior recurrent dislocation of the shoulder. J Bone Joint Surg Am 1970;52A: 1010–1016.
9. Patte D, Debeyre J. Luxations recidivantes de l'epaule. Encycl Med Chir. Paris-Technique chirurgicale. Orthopedie 1980;44265:4.4-02.
10. Sugaya H, Moriishi J, Dohi M, et al. Glenoid rim morphology in recurrent anterior glenohumeral instability. J Bone Joint Surg Am 200385A:878–884.
11. Walch G, Boileau P. Latarjet-Bristow procedure for recurrent anterior instability. Tech Shoulder Elbow Surg 2000;1:256–261.